The purpose of this project is to identify, and explore the nature of, psychophysiological characteristics that are related to depression. In particular, we are interested in the frontal lobe and its role in affective expression and regulation in depressed and non-depressed adolescent mothers and their infants. We seek to replicate our previous finding that infants of depressed and non-depressed mothers differ in their patterns of frontal EEG activity during emotional situations. Furthermore, we plan to extend this research by examining the contemporaneous and predictive relationships between measures of frontal lobe EEG activity and autonomic arousal, and "depressed" behavior in mothers and their infants. Participants will be 120 infants and their adolescent mothers, approximately half of whom will be depressed as reflected in their scores on the Center for Epidemiological Studies-Depression Scale. Infants' patterns of frontal EEG and autonomic arousal in resting and emotion-eliciting conditions will be studied longitudinally at 10, 20 and 30 months of age, along with measures of maternal depression and maternal affective and interactive style with her infant. Infants' social and affective behavior, and cognitive and language abilities also will be assessed longitudinally. A central question to be addressed by the longitudinal study is whether it is the case that infants' psychophysiological responses are relatively stable over time despite changes in maternal report of depression and/or maternal behavior toward the infant (Model 1), or, alternatively, that infants' psychophysiological responses are closely linked at any given time to mother's current report of depressive symptoms and/or her behavior toward her infant (Model 2). Finally, when infants are 10 and 30 months of age, frontal EEG activity and autonomic arousal also will be measured in the depressed and non-depressed adults were found to differ in their patterns of resting frontal EEG activity, and also allow us to examine more closely the linkage between infants' and mothers' affective and physiological responses.